/**
* Returns the last set of the expression
*
* (the last-charater-projection of the language)
*/
private static IntCharSet last(RegExp re)
{
RegExp2 r;
switch (re.type)
{
case sym.BAR:
r = (RegExp2)re;
return(last(r.r1).add(last(r.r2)));
case sym.CONCAT:
r = (RegExp2)re;
if (containsEpsilon(r.r2))
{
return(last(r.r1).add(last(r.r2)));
}
else
{
return(last(r.r2));
}
case sym.STAR:
case sym.PLUS:
case sym.QUESTION:
return(last((RegExp)((RegExp1)re).content));
case sym.CCLASS:
return(new IntCharSet((ArrayList)((RegExp1)re).content));
case sym.CCLASSNOT:
IntCharSet all = new IntCharSet(new Interval((char)0, maxChar));
IntCharSet set = new IntCharSet((ArrayList)((RegExp1)re).content);
all.sub(set);
return(all);
case sym.CHAR:
return(new IntCharSet((char)((RegExp1)re).content));
case sym.STRING:
String content = (String)((RegExp1)re).content;
if (content.Length > 0)
{
return(new IntCharSet(content[content.Length - 1]));
}
else
{
return(new IntCharSet());
}
case sym.MACROUSE:
return(last(macros.getDefinition((String)((RegExp1)re).content)));
}
throw new Exception("Unkown expression type " + re.type + " in " + re); //$NON-NLS-1$ //$NON-NLS-2$
}
/**
* Stores a new macro and its definition.
*
* @param name the name of the new macro
* @param definition the definition of the new macro
*
* @return <code>true</code>, iff the macro name has not been
* stored before.
*/
public bool insert(String name, RegExp definition)
{
#if DEBUG_TRACE
log.WriteLine("insert(String name = \"{0}\", RegExp definition = {1})", name, definition);
#endif // DEBUG_TRACE
if (Options.DEBUG)
{
Out.debug("inserting macro " + name + " with definition :" + Out.NL + definition); //$NON-NLS-1$ //$NON-NLS-2$
}
used[name] = false;
bool new_entry = !macros.ContainsKey(name);
macros[name] = definition;
return(new_entry);
}
public int insert(int line, ArrayList stateList, RegExp regExp, Action action,
Boolean isBOL, RegExp lookAhead)
{
if (Options.DEBUG)
{
Out.debug("Inserting regular expression with statelist :" + Out.NL + stateList); //$NON-NLS-1$
Out.debug("and action code :" + Out.NL + action.content + Out.NL); //$NON-NLS-1$
Out.debug("expression :" + Out.NL + regExp); //$NON-NLS-1$
}
states.Add(stateList);
regExps.Add(regExp);
actions.Add(action);
BOL.Add(isBOL);
look.Add(lookAhead);
lines.Add(line);
return(states.Count - 1);
}
/**
* Returns true iff the matched language contains epsilon
*/
private static bool containsEpsilon(RegExp re)
{
RegExp2 r;
switch (re.type)
{
case sym.BAR:
r = (RegExp2)re;
return(containsEpsilon(r.r1) || containsEpsilon(r.r2));
case sym.CONCAT:
r = (RegExp2)re;
if (containsEpsilon(r.r1))
{
return(containsEpsilon(r.r2));
}
else
{
return(false);
}
case sym.STAR:
case sym.QUESTION:
return(true);
case sym.PLUS:
return(containsEpsilon((RegExp)((RegExp1)re).content));
case sym.CCLASS:
case sym.CCLASSNOT:
case sym.CHAR:
return(false);
case sym.STRING:
return(((String)((RegExp1)re).content).Length <= 0);
case sym.MACROUSE:
return(containsEpsilon(macros.getDefinition((String)((RegExp1)re).content)));
}
throw new Exception("Unkown expression type " + re.type + " in " + re); //$NON-NLS-1$ //$NON-NLS-2$
}
/**
* Constructs a two state NFA for char class regexps,
* such that the NFA has
*
* exactly one start state,
* exactly one end state,
* no transitions leading out of the end state
* no transitions leading into the start state
*
* Assumes that regExp.isCharClass(macros) == true
*
* @param regExp the regular expression to construct the
* NFA for
*
* @return a pair of integers denoting the index of start
* and end state of the NFA.
*/
private void insertNFA(RegExp regExp, int start, int end)
{
switch (regExp.type)
{
case sym.BAR:
RegExp2 r = (RegExp2)regExp;
insertNFA(r.r1, start, end);
insertNFA(r.r2, start, end);
return;
case sym.CCLASS:
insertClassNFA((ArrayList)((RegExp1)regExp).content, start, end);
return;
case sym.CCLASSNOT:
insertNotClassNFA((ArrayList)((RegExp1)regExp).content, start, end);
return;
case sym.CHAR:
insertLetterNFA(
false, (char)((RegExp1)regExp).content,
start, end);
return;
case sym.CHAR_I:
insertLetterNFA(
true, (char)((RegExp1)regExp).content,
start, end);
return;
case sym.MACROUSE:
insertNFA(macros.getDefinition((String)((RegExp1)regExp).content),
start, end);
return;
}
throw new Exception("Unknown expression type " + regExp.type + " in NFA construction");
}
public int NFASize(Macros macros)
{
int size = 0;
IEnumerator e = regExps.GetEnumerator();
while (e.MoveNext())
{
RegExp r = (RegExp)e.Current;
if (r != null)
{
size += r.size(macros);
}
}
e = look.GetEnumerator();
while (e.MoveNext())
{
RegExp r = (RegExp)e.Current;
if (r != null)
{
size += r.size(macros);
}
}
return(size);
}
public RegExp2(int type, RegExp r1, RegExp r2) : base(type)
{
this.r1 = r1;
this.r2 = r2;
}
/**
* Constructs an NFA for regExp such that the NFA has
*
* exactly one start state,
* exactly one end state,
* no transitions leading out of the end state
* no transitions leading into the start state
*
* @param regExp the regular expression to construct the
* NFA for
*
* @return a pair of integers denoting the index of start
* and end state of the NFA.
*/
public IntPair insertNFA(RegExp regExp)
{
IntPair nfa1, nfa2;
int start, end;
RegExp2 r;
if (Options.DEBUG)
{
Out.debug("Inserting RegExp : " + regExp);
}
if (regExp.isCharClass(macros))
{
start = numStates;
end = numStates + 1;
ensureCapacity(end + 1);
if (end + 1 > numStates)
{
numStates = end + 1;
}
insertNFA(regExp, start, end);
return(new IntPair(start, end));
}
switch (regExp.type)
{
case sym.BAR:
r = (RegExp2)regExp;
nfa1 = insertNFA(r.r1);
nfa2 = insertNFA(r.r2);
start = nfa2.end + 1;
end = nfa2.end + 2;
addEpsilonTransition(start, nfa1.start);
addEpsilonTransition(start, nfa2.start);
addEpsilonTransition(nfa1.end, end);
addEpsilonTransition(nfa2.end, end);
return(new IntPair(start, end));
case sym.CONCAT:
r = (RegExp2)regExp;
nfa1 = insertNFA(r.r1);
nfa2 = insertNFA(r.r2);
addEpsilonTransition(nfa1.end, nfa2.start);
return(new IntPair(nfa1.start, nfa2.end));
case sym.STAR:
nfa1 = insertNFA((RegExp)((RegExp1)regExp).content);
start = nfa1.end + 1;
end = nfa1.end + 2;
addEpsilonTransition(nfa1.end, end);
addEpsilonTransition(start, nfa1.start);
addEpsilonTransition(start, end);
addEpsilonTransition(nfa1.end, nfa1.start);
return(new IntPair(start, end));
case sym.PLUS:
nfa1 = insertNFA((RegExp)((RegExp1)regExp).content);
start = nfa1.end + 1;
end = nfa1.end + 2;
addEpsilonTransition(nfa1.end, end);
addEpsilonTransition(start, nfa1.start);
addEpsilonTransition(nfa1.end, nfa1.start);
return(new IntPair(start, end));
case sym.QUESTION:
nfa1 = insertNFA((RegExp)((RegExp1)regExp).content);
addEpsilonTransition(nfa1.start, nfa1.end);
return(new IntPair(nfa1.start, nfa1.end));
case sym.BANG:
return(complement(insertNFA((RegExp)((RegExp1)regExp).content)));
case sym.TILDE:
nfa1 = insertNFA((RegExp)((RegExp1)regExp).content);
start = nfa1.end + 1;
int s1 = start + 1;
int s2 = s1 + 1;
end = s2 + 1;
for (int i = 0; i < numInput; i++)
{
addTransition(s1, i, s1);
addTransition(s2, i, s2);
}
addEpsilonTransition(start, s1);
addEpsilonTransition(s1, nfa1.start);
addEpsilonTransition(nfa1.end, s2);
addEpsilonTransition(s2, end);
nfa1 = complement(new IntPair(start, end));
nfa2 = insertNFA((RegExp)((RegExp1)regExp).content);
addEpsilonTransition(nfa1.end, nfa2.start);
return(new IntPair(nfa1.start, nfa2.end));
case sym.STRING:
return(insertStringNFA(false, (String)((RegExp1)regExp).content));
case sym.STRING_I:
return(insertStringNFA(true, (String)((RegExp1)regExp).content));
case sym.MACROUSE:
return(insertNFA(macros.getDefinition((String)((RegExp1)regExp).content)));
}
throw new Exception("Unknown expression type " + regExp.type + " in NFA construction");
}
/**
* Checks for illegal lookahead expressions.
*
* Lookahead in C# Flex only works when the first expression has fixed
* length or when the intersection of the last set of the first expression
* and the first set of the second expression is empty.
*
* @param r1 first regexp
* @param r2 second regexp (the lookahead)
*
* @return true iff C# Flex can generate code for the lookahead expression
*/
private static bool checkLookAhead(RegExp r1, RegExp r2)
{
return(r2 == null || length(r1) > 0 || !(last(r1).and(first(r2)).containsElements()));
}
/**
* Returns length if expression has fixed length, -1 otherwise.
*/
private static int length(RegExp re)
{
RegExp2 r;
switch (re.type)
{
case sym.BAR: {
r = (RegExp2)re;
int l1 = length(r.r1);
if (l1 < 0)
{
return(-1);
}
int l2 = length(r.r2);
if (l1 == l2)
{
return(l1);
}
else
{
return(-1);
}
}
case sym.CONCAT: {
r = (RegExp2)re;
int l1 = length(r.r1);
if (l1 < 0)
{
return(-1);
}
int l2 = length(r.r2);
if (l2 < 0)
{
return(-1);
}
return(l1 + l2);
}
case sym.STAR:
case sym.PLUS:
case sym.QUESTION:
return(-1);
case sym.CCLASS:
case sym.CCLASSNOT:
case sym.CHAR:
return(1);
case sym.STRING: {
String content = (String)((RegExp1)re).content;
return(content.Length);
}
case sym.MACROUSE:
return(length(macros.getDefinition((String)((RegExp1)re).content)));
}
throw new Exception("Unkown expression type " + re.type + " in " + re); //$NON-NLS-1$ //$NON-NLS-2$
}